Biodiesel is a recycled and biological fatty acid ester manufactured from animal fat, used cooking oil, botanical oil, and algae. Biodiesel is a viable replacement and more environmentally friendly and sustainable alternative for diesel oil since it is made from renewable resources and has qualities similar to diesel oil. When producing biodiesel from renewable resources, the trans-esterification method is utilized. This method manufactures fatty acid alkyl ester (biodiesel) and crude glycerol, which is accomplished by replacing the organic group (alkyl) of alcohol with the organic group of the primary triglyceride component of the raw materials. When the biodiesel specifications meet the global standard established by the European Union's EN14214 or the American Society for Testing Materials (ASTM) for alternative fuels, it can be used in its purest form, known as B100 or blended with petroleum diesel at any concentration. B100 is the purest form of biodiesel. The temperature of the reaction, molar ratio of alcohol to oil, type of alcohol used, type of catalyst utilized and the concentration of the catalyst are all parameters that must be considered during the biodiesel synthesis process. Moreover, the amount of time that the reaction is allowed to continue, the existence of humidity, and the amount of free fatty acids also significantly influence the production process. To minimize the costs of producing biodiesel, selecting the most effective methods is essential.